THE KINDLING-ACTIVATED NEURONAL NETWORK - RECRUITMENT OF SOMATOSTATIN-SYNTHESIZING NEURONS

The present study demonstrates the anatomical extent of the kindling-a ctivated neuronal network in general, and specifically the recruitment of extrahippocampal somatostatin (SST)-synthesizing neurons into this network. It has been known that SST neurons of the hippocampal format ion are activated during episodes of seizure, however, it was not know n if this activation was a local event or extended to other areas in t he brain. We were therefore interested in determining if and which SST neurons outside the hippocampal formation might be recruited into thi s seizure-activated neuronal network. Using the kindling model of seiz ure elicitation, expression of the Fos protein in activated, depolariz ed neurons was utilized to identify seizure-activated neurons. Subsequ ently, the mRNA for SST was identified through in situ hybridization i n the same tissue section, allowing the identification of seizure-acti vated, SST-synthesizing neurons. The results show that: (a) the majori ty of SST-synthesizing neurons in the forebrain and diencephalon becam e activated during the kindling development; (b) their recruitment int o the kindling-activated neuronal network occurred progressively; and, (c) these SST-synthesizing neurons represented a component of the kin dling-activated neuronal network throughout the development of kindlin g-induced seizures. Copyright (C) 1996 Elsevier Science Inc.